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Global Climate Change and Its Impacts

III. Manifestations of Long-Term Cumulative Effects and Irreversibility
in Ecosystems

Against the grand context of climate change, ecosystems are enduring unprecedented
pressures. The long-term impacts of climate change on ecosystems gradually materialize
through persistent cumulative effects, often leading to irreversible consequences that pose
severe threats to biodiversity and ecosystem stability.
The long-term cumulative effects manifest in multiple dimensions within ecosystems.
In terms of species’ living environments, persistent climate change alters patterns of key cli-
matic elements such as temperature and precipitation. As global average temperatures gradu-
ally rise, the originally suitable temperature ranges for many species are being disrupted. For
instance, some cold-temperate species are seeing their habitats gradually retreat toward high-
er latitudes or altitudes due to inability to adapt to rising temperatures. During this process,
the area of suitable habitats continues to shrink, leading to significant reduction in species’
distribution ranges. Over long-term accumulation, some species may face extinction risks
due to loss of sufficient living space. Changes in precipitation patterns also have profound
impacts—the decrease in total precipitation or alterations in seasonal distribution create
survival challenges for species dependent on stable water sources. For wetland species, the
shrinkage of wetland areas caused by reduced precipitation damages their breeding, forag-
ing, and habitat spaces, resulting in sustained population decline over the long term.
Biological phenology is also profoundly affected by the long-term cumulative effects
of climate change. Phenology refers to the periodic changes in which organisms have long
adapted to climatic conditions, forming corresponding growth and developmental rhythms.
Climate warming has caused the spring phenological phases of many plants to occur earlier,
such as the advancement of flowering and leaf emergence times in plants. For plants reliant
on insect pollination, if their flowering periods become desynchronized with pollinator activ-
ity due to climate change, their pollination success rates will significantly decrease, thereby
affecting their reproduction and population renewal.In animals, aspects such as bird migra-
tion timing and breeding periods have also undergone alterations due to climate change.
Over long-term accumulation, the originally stable ecological relationships between species
become disrupted, the structures of food chains and food webs are impacted, and the func-
tionality and stability of entire ecosystems suffer severe consequences.
The impacts of climate change on ecosystems often lead to irreversible consequences,
with species extinction being the most severe manifestation. When species endure prolonged
climate stress and cannot find suitable habitats through adaptation or migration, their ex-
tinction risk dramatically increases. For instance, many island species with geographical
isolation possess narrow ecological niches and limited adaptability. In the face of climate
change-induced rising sea levels, shrinking island areas, and altered climatic conditions,
these species often lack sufficient space and resources to adapt, making extinction highly
likely. Once a species becomes extinct, its unique genetic library is permanently lost, and the

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